1. The Field of the Invention
The present invention relates generally to apparatus for the illumination of endoscopic and borescopic fields, in minimally invasive surgical (MIS) procedures, general or diagnostic medical or industrial procedures using endoscopes or borescopes, respectively. More particularly, embodiments of the invention relate to use of removable illumination and imaging systems in endoscopic and borescopic procedures, as a means of illumination and image capture.
2. The Relevant Technology
Laparoscopy is used in both diagnostic and surgical procedures. Currently, MIS procedures, as opposed to open surgical procedures, are routinely done in almost all hospitals. Minimally invasive techniques minimize trauma to the patient by eliminating the need to make large incisions. This both reduces the risk of infection and reduces the patient's hospital stay. Laparoscopic and endoscopic procedures in MIS use different types of endoscopes as imaging means, giving the surgeon an inside-the-body view of the surgical site. Specialized endoscopes are named depending on where they are intended to look. Examples include: cystoscope (bladder), nephroscope (kidney), bronchoscope (bronchi), laryngoscope (larynx+ the voice box), otoscope (ear), arthroscope (oint), laparoscope (abdomen), gastrointestinal endoscopes, and specialized stereo endoscopes used as laparoscopes or for endoscopic cardiac surgery.
The endoscope may be inserted through a tiny surgical incision to view joints or organs in the chest or abdominal cavity. More often, the endoscope is inserted into a natural body orifice such as the nose, mouth, anus, bladder or vagina. There are three basic types of endoscopes: rigid, semi-rigid, and flexible. The rigid endoscope comes in a variety of diameters and lengths depending on the requirements of the procedure. Typical endoscopic procedures require a large amount of equipment. The main equipment used in conjunction to the visual part of the endoscopic surgery are the endoscope body, fiber optics illumination bundles, illumination light source, light source controller, imaging camera, camera control module, and video display unit.
The laparoscope is a rigid endoscope as illustrated in FIG. 1. It allows for visualization of the abdominopelvic cavities for diagnostic or surgical techniques. The laparoscope is inserted into the peritoneal cavity via a cannula that runs through the abdominal wall. There are many different features of laparoscopes, such as the size and field of vision, which determine the effectiveness of the instrument.
As illustrated in FIG. 1, the basic laparoscope is made up of a long thin tube 101 with an eyepiece 103 at one end for viewing into the patient. Fiber optic light introduced to the endoscope at fiber port 102, and launched into fiber optics 302 (FIG. 3), passes through the endoscope body 101, illuminating the area 304 that is being observed, as illustrated by radiation pattern 306 in FIG. 3. Laparoscopes are characterized by diameter and the direction of view. The direction of view is the angle 107 between the axis 105 of the laparoscope and the center field of view 106, as illustrated in FIG. 1. Typical endoscopes have lengths of approximately 30 cm and diameters in the range of 4 to 10 mm. Laparoscopes consist of two important lenses, the ocular lens at the eyepiece and the objective lens 308 at the distal end of the endoscope 300 in FIG. 3. Other lens sets acting as relay lenses 310 in FIG. 3, are used in-between the objective lens and the eye piece or the CCD camera or image position 312. Imaging rays 314 traverse the length of the scope through all the imaging optics.
The rigid endoscope also comes in different viewing angles: 120 degree or retrograde, for viewing backward; 90 degree and 70 degree for lateral viewing; 30 degree (104 as illustrated in FIG. 1) and 45 degree for forward oblique views; and 0 degree for forward viewing. The angle of the objective lens 308 used is determined by the position of the structure to be viewed.
Other surgical instruments and tools are also inserted into the body, for the operation and specific surgical manipulation by the surgeon. The insertion is done through open tubes provided inside the endoscope body for instrument insertion, such as in gastrointestinal endoscopes, or through separate incisions in the abdominal or chest wall 202, as illustrated in FIG. 2, using cannula 200 (straight or curved stainless steel or plastic tubes which are inserted into a small opening or incision in the skin). The cannula opening at the proximal end 204 outside the body is used to guide different instruments inside the body, where they are exposed to the inside of body at the distal end 206 of the cannula. Cannulas can make a seal at the incision site 208.
In a typical gastrointestinal endoscope, a tool opening is provided at the distal end of the scope, where inserted medical instruments gain access to the body following the scope body.
Endoscopes can be diagnostic, for observation only, or operative, having channels or ports for irrigation, suction, and the insertion of accessory instruments when a surgical procedure is planned. Thus, endoscope bodies also could provide mechanical or electrical control sections, buttons for valves such as a suction valve, a CO2 valve, a water bottle connector, a water feed, a suction port, etc. The common component that all endoscopes must be equipped with is a light guide section for illumination.
An illustration showing typical endoscope optics is shown in FIG. 3. Common imaging sections of the endoscope are an ocular or eyepiece, relay lenses 310 (in the case of rigid scopes), a flexible imaging fiber-optic bundle (in the case of flexible scopes), and an objective lens system 308. Endoscopes are either used as stand alone units, with the surgeon looking into the scope from the ocular or eye piece of the endoscope, or in conjunction with digital cameras, where an image of the surgical site is incident on the image capture device (charge coupled device or CCD) of the camera. Using a display device, the surgeon performs the operation looking at the image on the video monitor.
With recent technology improvements in the field of electronic imaging reducing the size of the image capture device (e.g., CCD), some endoscopes used in MIS and diagnostic procedures are equipped with a high resolution distal end camera system, commonly referred to as Chip on a Stick, one example of which is illustrated in FIG. 4 as camera system 400. These flexible endoscopes use a CCD chip 402 at the distal end of the endoscope directly capturing the image through the objective lens 404, in which case the flexible part 406 of the endoscope body contains only power and communication wires for the CCD camera at the distal tip, rather than imaging optics 408 located in a rigid portion 404 of the endoscope. Light guides 410 running the length of the endoscope are still necessary for this type of electronic scope to provide adequate lighting 412 of the surgical site 414 for imaging purposes.
Other, more complicated MIS systems make use of robotic surgical tools and instruments, and/or provide stereoscopic images of the surgical site for the surgeon, improving the surgeon's dexterity, precision and speed of operation. In these more sophisticated MIS imaging applications more specific types of illumination systems or multiple illuminators are used.
Color CCD cameras use alternate color dies on the individual CCD pixels, to capture color images. Green and red, and green and blue pixels are alternated in rows. This spatial color sampling limits the color resolution of the color CCD cameras, since each pixel is dedicated to capturing a single color in the color image.
3 chip CCD cameras (red CCD chip, blue CCD chip, and green CCD chip) are also used in high resolution applications, where all the pixels in each CCD are dedicated to detecting the single color content of the image. The individual color captured images from the 3 CCDs are then put together electronically, as the multi-color image is reproduced on the viewing display. Three chip CCD cameras are expensive and bulky.
Recent advances in illumination and image capture technology demonstrate the rapid changes that can occur in the capabilities of emerging illumination and imaging systems. For instance, very compact high mega pixel cameras are currently being incorporated widely in cellular phone cameras, whereas just a few years ago this was not possible. It is quite likely that other technological advances in imaging and illumination will occur that can be used in endoscopic medical devices. And, although it may be desirable to incorporate the latest technological advances in illumination and imaging into an endoscopic medical device, this is often impossible without designing and purchasing a brand new replacement device having the improved technology. This complete new solution, however, can be prohibitively expensive especially in the circumstances that the medical providers are under high pressure to reduce cost. Incorporation of the advanced high quality opto-electronics in current and future low cost medical procedures can also be nearly impossible.
Due to delicate and complicated nature of current endoscope illumination and vision technology, current high performance endoscopes are often limited in sterilization capability, and for the major part not autoclavable. This shortcoming not only limits the life time of these endoscopes to limited number of procedures, but also creates possibility of infection with multiple sterilization and disinfection procedures performed on the current scopes.